A 3.5 angstrom units resolution electron density map is to be prepared within the next few weeks. If it is interpretable, a good deal of effort will go into model building of the three quasi-equivalent protein subunits and that of the RNA secondary structure as is visible. In addition, one other heavy atom derivative (AuCl2) is now being collected to provide further improvement to the electron density map. Data collection of 3.0 angstrom units data has been investigated and should be possible by cooling the crystals to 4 degrees centigrade. Crystals of metal-free, swollen virus are available. This form probably represents a stage in the disassembly of the virus particle after entering the cell. Investigation of these crystals is just starting. Attempts at crystallizing the partly disassembled virus produced by KCl treatment have also been initiated. Possible polysaccharide receptor sites on the virus surface are to be investigated by various binding studies as well as crystallographically.